add theme

themes/butterfly/source/css/index.styl

@@ -0,0 +1,15 @@
+if hexo-config('css_prefix')
+  @import 'nib'
+
+@import '_third-party/normalize.min.css'
+// project
+@import 'var'
+@import '_global/*'
+@import '_highlight/highlight'
+@import '_page/*'
+@import '_layout/*'
+@import '_tags/*'
+@import '_mode/*'
+
+// search
+@import '_search/index'